1. Field of the Invention
The present invention is directed to a set screw and, more specifically, to a set screw having an elastic insert such as a nickel-titanium alloy.
2. Description of Related Art
Set screws are typically utilized to secure a component, such as a pulley or a gear onto a shaft. Exemplary types of set screws include cup point, cone point, flat point, oval point, dog point, and soft point set screws. Cup point and cone point set screws are designed to cut into the shaft, thereby mechanically binding to the shaft. It is difficult to disassemble a component mated to the shaft by cup point or cone point set screws unless the clearance between the mated component and shaft is sufficiently large. Furthermore, the cup point and cone point set screws permanently damage the surface of the shaft. The flat point and oval point set screws are designed to cause less damage in that such screws depend on friction. Therefore, the flat point and oval point set screws carry much lower moments than the cup point and cone point set screws. However, the flat point and oval point set screws may be used within a groove or on a flat machined into the shaft in order for such screws to have substantially equal moments as the cup point and cone point set screws. Even then, though, such screws often come loose when exposed to vibration, dynamic forces, or overload. The dog point set screw is designed to fit in a groove machined into the shaft and is intended to replace dowel pins. The soft point set screw utilizes a nylon or brass insert as a tip for the screw and therefore causes no damage to the shaft. However, the nylon or brass insert tip is designed to only carry relatively small loads through friction. In due course, because of relaxation, the nylon or brass insert tip loses gripping force.
It is, therefore, desirable to overcome the above problems and others by providing a set screw designed to secure high loads, withstand dynamic loads and vibrations, and produce no damage to a securing surface.